Many homeowners and businesses use an alarm system to protect their real and personal property. An alarm system can be used to detect physical disturbances on a premise and alert an owner and/or authorities about the physical disturbance. An alarm system can be a stand alone system or integrated within a larger security system context (e.g., that also includes armed guards, CCTV, etc.)
A typical alarm system includes a number of sensors linked to a control panel. The control panel includes an interface that can be used by a human user to arm, or in many cases activate monitoring (e.g., when leaving their residence) and disarm, or in many cases deactivate (e.g., when re-entering their residence) monitoring of the sensors. A control panel can also include other functions, such as, for example, a physical duress alarm, two-way voice communication, a siren, etc. Different types of sensors are configured to monitor for different physical disturbances. For example, a door/window sensor is configured to detect when a door/window has been opened, a motion detector is configured to detect motion, a glass break detector can be configured to detect the physical event of glass being broken or even to detect the sound of breaking glass.
Monitoring can include a control panel locally monitoring sensor activity on a premise as well as a central monitoring system remotely monitoring the alarm system. To facilitate remote monitoring an alarm system communicates signals (alarm events and/or non alarm events) to the central monitoring station via a phone line, cellular transmission, over the Internet, etc. Thus, the control panel is typically monitored in some way. For residential alarm systems, a remote central monitoring station can be a third party vendor or in some cases the same company that installed the alarm system. For commercial and industrial alarm systems, monitoring is sometimes performed on the premises, for example, by security or other personnel. In these types of commercial and industrial settings the control panel can be integrated into a larger security system context.
In any event, when sensor monitoring is activated and a sensor indicates a physical disturbance, the control panel can activate an alarm. In response to an alarm, the control panel can activate an audible siren and/or send an indication of the alarm to a central monitoring entity via an alarm event signal. The monitoring entity can then initiate a response, such as, for example, contacting the premise owner, sending security personnel, contact authorities, etc.
Most alarm systems include a mix of passive and active sensors. A passive sensor monitors for naturally occurring changes in it surrounding environment. Passive sensors include door/window sensors, glass break sensors, and some types of motion sensors. For example, a door sensor monitor can indicate a transition from a close to an open circuit when a monitoring door is open. A Passive Infrared (PIR) motion passive accepts incoming infrared radiation but does not emit an infrared beam. A PIR motion detector detects differences in emitted infrared energy between different objects, such as, for example, when a human is present in front of a wall.
Active sensors include some types of motion sensors. Active sensors detect energy input from a source other than that which is being sensed. In many alarm systems, an active sensor provides its own energy for illumination of an object. That is, an active sensor emits energy (e.g., IR, visible light, etc.) into its surrounding environment and measure how the surrounding environment interacts with the energy. However, emission and detection of energy can be performed by different devices. An active sensor can measure an angle of reflection of emitted energy, how long energy took to return to the sensor, etc., for example, to detect motion. Since emitting energy into a surrounding area consumes power, additional wiring is typical required connecting active sensors to a wired power source.
In some alarm systems, even those that use only passive sensors, some or all sensors communicate with a control panel via hardwired links. When a sensor detects a physical disturbance, an indication of the disturbance is communicated to the control panel over a hardwired link. For door/window sensors, the indication can be transition from a closed to an open circuit (e.g., a door sensor detecting that a door is open). For motion sensors, the indication can be a signal of an irregular energy pattern in the surrounding area.
In other alarm systems, some or all sensors communication with a control panel via wireless links. For wireless communication, each wireless sensor includes a wireless transmitter that transmits data on a specified radio frequency. The control panel includes wireless receiver that is tuned to receive data on the specified frequency. Most wireless sensors and wireless control panels are digital and send/receive digital data, preventing the use of wired sensors. However, some wireless control panels do provide limited capability to connect passive wired sensors (e.g., providing one or two connections for passive wired sensors).
When considering how to supplement an alarm system with new sensors one option is to install additional wired sensors. However, installing new wired sensors requires running additional wires, which can be time consuming and costly.
On the other hand, there a number of benefits to using wireless technologies to supplement existing alarm systems. One advantage is eliminating the time and cost associated with running wire within an existing structure. Further, adding a wireless sensor to an alarm system that already includes a wireless control panel is relatively simple. A new wireless sensor is placed and the control panel is programmed to monitor the new wireless sensor.
Unfortunately, it can be problematic to supplement an existing hardwired alarm system (e.g. that already includes a number of wired sensors) with additional wireless sensors. Some existing wired control panels are not compatible with wireless sensors and wireless sensor protocols. Thus, using even one wireless sensor with an existing wired alarm system can require replacement of an existing wired control panel with a wireless control panel. However, switching to a wireless control panel significantly limits (and depending on the wired control panel potentially eliminates) the use of existing wired sensors. To regain the functionality of the existing wired sensors, corresponding wireless sensors must be purchased and installed.
Thus, when considering how to supplement an existing wired alarm system with addition sensors, a user is often forced to make a difficult choice. On one hand, the user can chose to install additional wired sensors. However, choosing to use additional wired sensors results in the time and cost burdens associated with running additional wiring. On the other hand, the user can chose to install new wireless sensors. However, choosing to use wireless sensors typically requires replacement of an existing wired control panel with a wireless control panel. Replacement of the existing wired control panel can result in loss of functionality for many wired sensors (due either to sensor type or number of sensors). To regain the lost functionality, the user is typically required to purchase corresponding wireless sensor replacements.